High-tension circuits



Aprii 19, 1927. 1,624,951

H. B. HOLTHOUSE HIGH TENSION CIRCUITS Filed July 15, 1922 2 Sheets-Sheet 2 Patented Apr. 19,

HARRY nnoL'rnousE, or CHICAGO, rumors.

HIGH-TENSION CIRCUITS.

Application filed July 15, 1922. Serial 110,575,211.

invention relates to electrical circuits use in ignition circuits or for excitation of X-ray tubes, vacuum electrodes, ultra violet ray generation, etc.

A One of the features of my invention is the provision in a circuit having breaker points across a source of current, of a fixed spark gap with the circuit so arranged that the spark gap eliminates entirely, or to a substantial degree,

when they are operated the sparking at the points so as to prevent burning up of these contacts. Furthermore,

the provision of such a ga in such a circuit, I find, aids and pro ongs the dura tion of the are caused by the operation of f A, a direct current generator B having a the breaker points. my arrangement is th oscillating circuit is ing a much hig Another feature 0 at the resistance of the reduced thereby causher frequency and heavier and more contmuous. discharge from the secondary of theoscillation transformer effecting more comple due to the longer ti spacing forms. The gap als ondary voltage.

Another feature 0 of the spark te trains of oscillations me element and fixed gap where the are 0 determines the secf my arrangement is' that higher frequencies of oscillations are obtained as the gap prevents damping of the oscillations because they start earher,

thus allowing a greater period of timefor oscillations. Also, the gap forms a fixed sparking point of definlte and lower resistance and thus more constant than due to their beginning at of operation in the breaker There are other fe of my improved cir trains of oscillations are where they may vary different periods points.

atures and advantages cuit arrangement and.

these will be pointed out in the ensuing part of the specification and accompanylng claims.

For a better under tion reference 1s to panying drawings in which Fig. 1 shows one standing of my invenbe had to the accomform of my mvention more particularly adapted for the excitation of. X-ray tubes, vacuum violet ray generation etc., with various interchangeable ways of exciting the circuit;

Fig. 2 shows another form tion arranged more of m invenparticularly or igni electrodes, ultra tion purposes with the distribution in the high potential or secondary circuit;

Fig. 3 is another form of my invention arranged more particularly for an ignition circuit and withthe distribution in the primary circuit; and i Fig. 4 is a cross sectional view of an oscillation transformer adapted for use in my circuit and with a spark plug directly connected therewith.

Referring now more in detail to the form of my invention as shown in Fig. 1, a suitable source of exciting current 1s provided and I have shown three different sources adapted to be interchangeably connected by way of illustration. These three sources comprise a direct current or battery source separately excited field which may be by way of a-permanent magnet or electrically excited, and a third an alternating current generator having a ermanent magnet or separately excited field. I may also employ an alternating current from the usual alternating current feed, in place of the battery A, using the coil 37 as with A, but, of course, synchronizing the points 15, 16 with the current wave. Switches 10, 11 and 12 are adapted to connect these sources across thec'onductors 13- 14 which conductors are adapted toextend to the point of use such as to an oscillation transformer D.' Across the conductors which extend from the source of current to the point of use I connect breaker points suitably timed and adjusted as hereinafter more particularly described. For the source A, I provide breaker points or contacts 15- 16 shown as being 'operated by a rotatable cam 17 suitably tuned according to the use to which current is to be put. Across source B, I provide breaker points 1718 also suitably timed and adjusted according to their use. Across the alternating current source C I provide suitable breaker points 19-20 operating in synchronism with the generator C so that they will break on the peak of the wave and close substantially at zero.

It will thus be seen the breaker or contact points may be electromagnetically or mechanically operated and may be synchroit is to be air the current source and breaker contacts is a fixed spark gap 21 adjustable so as to be set according to the adjustment of the breaker contacts and the other circuit characteristics and out-put desired.

The conductors 13-1t. may, of. course, be extended to the desired'point of'use and I have shown an oscillation transformer D connected across these conductors havin a primary Winding 22 and secondary winding 23 with a spark gap 24 connected incircuit. A suitable condenser 25 is also shown connected in the primary circuit.

In Fig. 4 I: have shown an oscillation transformer which I have found suitable for use-inmy improved circuit, this device comprising a non-magnetic core 26 supporting a secondary winding 27 and primary winding 28. The primary winding is preferably on the outside and a few turns as compared to the inner or secondary winding 27 which is of comparatively great number of turns, the proportion varying, of course, according to the various circuit characteristics or results desired. The primary winding is connected across the binding posts 29-30 and thesecondary winding is connected to one terminal of the primary winding with the other terminal extending to the central electrode 31 of the sparking points 24. The othervelect-rode, that is 32. is shown as the sleeve'portionof a spark plug secured to a cap 33 so as to hold a suitable porcelain 34 iniwhich the central electrode is carried. A now-metallic insulating case or sleeve 35 is supported between the cap 33 and cap 36, the inside being filled with an insulatin compound or insulating oil. In Fig. 4 have. shown the oscillation transformer as connected directly with a spark plug for. internal eombustion engines. It will be understood,.however, that the transformer is to be connected according to the use to which put, and may have the usual sparking points connected therewith such asare ordinarily emplo ed for high frequency. spark oscillations. vice is a spark plug trodes are preferably very heavy and:I-' ordi narily, employ alar er gap. than usual because I. have found t electrodes. quickly burn-i away. condenser 25 is also'insertedi Operation of Figure 1. Now as to the operation of Fig. 1, when A circular supplied with current from source A I pref-- erably insert an inductance coil 37 inthe lineso-as to raise the breaking voltage and effect a lag in the circuit at the time the breaker contacts 15-16 are interrupted. Assuming-that switch 10 is'closed and contacts 15-16 closed, upon their next interruption. the self induced voltage of inductance coil 37 rises but contacts 15-16 interhen the sparking de-- as in Fig. 4:,the elecee. ordinary spark;plug:

rupt fast enough to prevent any substantial sparking at their points of separation and the self induced voltage is not sutiicient to Jump across the spark gap 2i until the contacts 15-16 have reached a point of separation greater than that of the spark gap. At this time the c'rcuit including the spark gap 21, conductor 13, primary winding 22, condenser 25 and conductor 14 is in a closed oscillating circuit started by the sparking at gap 21. This, of course, sets up a high voltage; high frequency oscillating. circuit through the secondary winding 23 and sparking points 24 thus providing a low resistance path across the contacts 21 for the exciting source A. Thus, in this circuit I have a high and low frequency, high and low voltage and heavy secondary current characteristic. \Vith the breaker points 15-16 working at the ordinary high speed the-oscillations across 24 continue until the source A is again short circuited by the closing of the points 15-16 and upon their next interruption excitation of the oscillation transformer and spark points 24 is again effected, this cycle of operations continuing upon each operation of the breaker points.

I have found that by the use of the circuitarrangement described,substantially all, if not all, of the sparking at the breaker points 15-16 is eliminated; the effectiveoscillations are more constant due to the fixed spark gap 21; and the period ofoscillations is increased. With the spark gap21-eliminated the oscillations-do not commence until the contacts 15-16 are closing aft-er theirv separation, while with the spark gap 21. provided I- allowv the oscillations to begin as soon as the self induced.- voltage has reached preferably a maximum where it jumps the gap21.

In-connection with this circuit it' will be understood, ofcourse, that the gap 21 isadjusted ,to-substantiallythe lowest voltage producedby the exciting source through the inductance coil 37. Thereby I make the time element more constant becausethe initial oscillations are effected by the beginning of the sparking at gap 21, the breaker points movingfastenough and far. enough apart, so-as-toprevent efiiectual sparking at said points 15-16.-

Assumingthat direct current source 'B-is connected; to the circuit through the switch. 11, the breaker points 17-18 are operatedthe same as points'1-5-16. Generator Bis a direct. current; generator with a separately excited field which may be electrically excited or by a pennanentmagnet and of. a type in which the direct short circuit by the breaker contacts is permitted.- In this circuitas in where the source A is used, the breaker points 17-18 interrupt to-permit the beginning of the oscillations-by the spark gap 21.

With the alternating current source (3 connected to the circuit by the switch 12,

breaker points 19-20 are operated in synplreferably Figure 2.

In Fig. 2 I have shown another form of my invention applied to an ignition circuit for a four cylinder internal combustion engine. The source of exciting current switches, breaker points and spark gap are shown as in Fig. 1 and numbered the same. The secondary winding of the oscillation transformer, however, instead of being connected directly to a spark electrode extends over a conductor 40 and then through a distributor 41 to the various spark plugs 42 to ground 43 to the return ground 44. this type of circuit the secondary or high potential is distributed to the sparking plugs which, of course, may be of' any number depending upon the number of cylinders in the engine. The breaker points must, of course, be in synchronism with the engine and where the alternating or magneto current is used the various elements must be properly timed so that the plugs spark at the proper time.

In using my improved circuit arrangement for ignition purposes, various advantages are secured in that the gap 21 being adjusted to the lowest breaking voltage, gives a constant timing to the starting of the sparking oscillations. Without the fixed sparking gap 21 the timing varies on account of. being started by the moving breaker points. This results in uneven timing as the breaking current jumps the ga at diflerent times. With the fixed gap the timing is more constant. Also the gap being of the usual large area maintains perfect adjustment and aids in the formation of an are, thus giving a more constant low resistance oscillating circuit which, of course, increases the out-put of the oscillation transformer secondary and increases and prolongs the oscillations.

In the operation of the circuit of Fig. 2, I

the initial surge through the primary of the transformer D is effected for each operation of the breakerpoints, resulting in a flow through the secondary 23, the distributor 41, the connected spark plug 42, and grounds 43-44. This initial high frequency oscillation or sparking across the spark lug electrodes 42 sets up a low resistance pat sobottom head that the current from the exciting source immediately flows over conductors 13-13,

secondary 23, conductor 40, distributor 41,.

spark plug 42 and grounds 43-44 to the he spark return side of the exciting source, thus providing a circuit for the primary current. It will thus be seen that the initial high potential current jumps the spark plug gap breaking down the resistance at this point so that a heavy surge of primary current of a coinpara'tively low voltage, flows over the spark gap of the plug, being limited only by the resistance of the secondary winding 23 of the transformer, which is unusually low.

In Fig. 2 l have shown a condenser 45, and switch 46 for cutting in the condenser to time the circuit to secure the proper phase relation or resonance between secondary discharge and the primary current surge. \Vithout the condenser the initial sparking is in advance of the primary current surge; with the condenser they are in phase. I find this of advantage in high compression engines.

Figure 3.

In Fig. 3 I have shown another form of my invention differing instead of distributing the high potential or secondary current as in Fig. 2, I distribute the low potential or primary current and then connect a coil for each of the spark plugs instead of using the individual coil as in Fig. 2. Thus by distributing, the low potential or primary current I eliminate the troubles arising from a high tension distribution where the connections and conductors are not properly insulated or maintained.

In the circuitof Fig. 3 the spark plugs 42 are grounded as before through the frame of the engine, but instead of being connected directly to the distributor as in Fig. 2 are connected to the secondary winding 23 of the transformer, the primary winding 22 of which is connected through the condenser 25 to ground or frame of the car. This ground 44 then leads to the ground 44 extending back to the exciting source of current. The middle or common point connection of the primary and secondary winding of the transformer is then connected through the distributor 41. Although I have shown individual condensers 25, it will be apparent that the primary'winding 22'may be connected in common through a single condenserto ground.

As to the operation of Fig. 3, it is thought that this will be readily understood in view of the description of the operation of Fig. 2.

I claim:

1. In an oscillation transformer and spark plug unit, an oscillation transformer coil, an insulating casing having a chamber with said transformer coil suspended therein, a for-the casing, a spark plug having a central electrode and supporting insulating porcelain therefor extending into the chamber throughsaid head and from Fig. 2 in that said plug having a metallic sleeve second electrode for attaching the plug to the casing head in sealed relation thereto and also hold the central electrode and porcelain in the casing, means for connecting the'coil to said central electrode, and an insulating compound in the chamber of said casing surrounding the coil and the central electrode in the casing to insulate the central electrode from the sleeve electrode.

2. In an oscillation transformer and spark plug unit, an oscillation transformer having a casing in which the transformer is suspended and filled with an insulating element, a spark plug. having a threaded metallic sleeve and a central electrode and insulating cover thereof the latter extending into the casing from an end thereof and connected with the coil of the transformer, and a head for the casing through which said plug electrode extends into the compound filled chamber in the casing, said head having a threaded bosson whichisaid plu sleeve is threaded and b which saicf plug is supported,- whereby te entire. unit is supported by the plug,-

In an oscillation transformer. andsparkplug unit, an oscillation transformenaninsulating casing therefor in which said transformer is suspended, at headfor said'casing, a spark plug having a threaded portion threaded on to the head to form a sealed connection to the casing and having an electrode extending into the casing and connected with said transformer to mechanically support the transformer coil independent of the casing, and an insulator in said casing filling in the space between the spark plug and transformer so as to vent sparking between exposed elements thereof.

' In witness whereof, I hereunto subscribe. my/name this 12th day of June A. D., 1922.

HARRY B. HOLTHQUSE.

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